Conventional hands-free operation for mobile phones, such as is described in the Bluetooth Hands-Free Profile Specification, utilizes a hands-free service connection between the Audio Gateway (AG) (e.g., the mobile phone) and the hands-free (HF) unit to provide hands-free operation to a user. When the mobile phone receives a phone call, or when the user initiates a call via the HF unit, the AG and the HF utilize the hands-free service connection to establish an audio communication channel between the AG and HF. A microphone and speaker of the HF unit operate in place of the mobile phone's microphone and speaker for the duration of the call. Thus, a user can speak into the HF's microphone and listen to call audio via the HF's speaker.
Traditional HF units support an active audio communication channel for a single mobile phone at any one time. Otherwise, the microphone and speaker would be used to carry more than one voice call, thereby resulting in user confusion. This is generally acceptable, since users can tell that the HF unit is active with another mobile phone and therefore do not expect that their calls will be accepted by the HF unit.